Experimental determination of synchronous machines reactances from DC decay at standstill

Estimating parameters of high power synchronous machines from steady state or transient AC operational tests requires a great deal of electrical power. This paper presents a procedure and its implementation for the determination of synchronous machines parameters from DC decay time-domain data acquired from standstill test measurements. The direct-axis and quadrature-axis reactances are indirectly found by processing the response of a synchronous machine at standstill to a step signal. This testing technique reduces the required power and minimizes the testing time, but presents a limited precision. The accuracy of the estimation of the machine parameters is improved by using floating-point quantization. Experimental results of a synchronous machine are finally presented to illustrate the applicability of this method.